Hey guys I have a 99 C5 with an iron block forged 370 roughly 9.5 to 1 CR. Im using stock 317 heads and I have a custom grind 228/228 .588 .588 114lsa cam. Im a TR6060 6 speed(09 ZR1 tranny=longer gears) and 342's in the back. I plan on reving to 7000-7200. I am building a single turbo setup. My goals for now are as much boost as I can run on 91 octane. I'd really like to get over 700whp if possible. The more the marrier! In the future I'll be switching to e85 and shooting for the moon.

My builder is Precision dealer and wants to use them. My question is which turbo? This is a street car and its taken to the track. I do more "side-by-side acceleration testing" on the street tho... : )

I was looking at te pT7675 or the PT88. Trying to not spend a ton on the turbo really... just want something that will work good.

What do you guys think? Any dynos that people can post would be great!

Thanks!

 

Both turbos you mentioned will get you the 700 rw goal. Either one would be a good pick in my opinion. You would get more power out of the pt 88 obviously but will not spool as fast as the 76.

 

My dyno numbers and times are below on a PT7875 (same as a 7675 basically). Seeing that you are a stick and are only looking for 700rwhp, I'd go that route. The PT88 uses a much larger and heavier turbine wheel which will spool much slower. The 7675 will make over 850rwhp through a stick with 370 cubes without issue.

 

My current goal is 700 plus whp on pump gas. Once I switch to e85 Id love 950-1000whp

 

A 7675 isn't going to do 1000rwhp on E85 on a 370. The PT88 will definitely get you close as the cost of some spool time. You may want to look into some of the budget Garrett units as well.

 

You could go with a Garret GTS76 with the 94mm turbine and Precision .96 a/r t4 housing. that way you can just swap in the cartage and compressor to the turbine housing when you want to go bigger down the road. My buddy has this setup on a stock short block 6l with hand ported heads. It's in a 4900lbs 4x4 truck that runs mid 10's at about 130

 

Yea the reason I am strictly using Precision is because my Turbo kit Fabricator(Brad at AFI) sells Precisions only so he gets a huge discount. I just want to make the most power on pump gas. I figured the PT88 would give me a decent amount more with the same amount of boost from the PT7675. Does that make sense?

I saw that somebody said there PT88 hit full boost at 4300-4500. Does anybody have any experience with either turbo? What RPM's are you hitting full boost at? Any dyno graphs?

 

if you want to hang the power to 7000-7200 rpm... i would choose the PT88

 

Yea, I'd like to. I will have slightly longer gearing than a ZR1 does. I have the 09 ZR1 tranny with 342's and a 27.8 inch tall tire. With a 7000-7200rpm redline... Probably 68-70mph in first gear, 92ish in second, 130ish in 3rd, etc.

I kinda figured I would be in a great power band most of the time. I will be using boost by gear. And I have a 2-step for launching.

I have seen people making 750whp on 14-15 psi and pump gas with the PT88... Thats nutz! Id love to acheive that!